Finding the right size pillow cover for a 20×20 insert seems simple, but getting it wrong can lead to a sloppy look. The answer to ‘what size pillow cover for 20×20 insert’ depends on the fullness and style you want.
Using the correct cover size is the secret to a professional, plump finish. A cover that’s too big will look baggy, while one that’s too small will overstuff and strain the seams. This guide will walk you through the simple rules and style choices to make sure your pillows look perfect every time.
What Size Pillow Cover For 20×20 Insert
For a standard, plump look on a 20×20 insert, you should use an 18×18 inch pillow cover. This is the most common and recommended size pairing. The insert will be slightly larger than the cover, creating a full, luxurious appearance without being overstuffed.
This 2-inch difference is a standard industry rule. It allows the insert to fill the cover completely, pushing out the corners for a crisp shape. Think of it like this: the insert is the filling, and the cover is the skin that needs to be snugly filled out.
Why the Pillow Cover Should Be Smaller Than the Insert
This might seem backwards at first. But a smaller cover is key for that desirable, plump look. Here’s why it works:
- Prevents Sagging: A same-size or larger cover will have empty space, causing the insert to shift and sag.
- Creates Fullness: The compression of the insert inside the smaller space forces it to expand outward, filling every corner.
- Defined Edges: You get sharp, clean edges instead of rounded, soft corners.
- Hides Wrinkles: The tension from the insert helps smooth out minor wrinkles in the fabric.
The Standard Size Rule for Pillow Covers and Inserts
Most home decor experts follow a simple formula. For a finished, professional look, your pillow cover should be 1 to 2 inches smaller than your insert on each side.
- For a 20×20 insert, use an 18×18 or 19×19 cover.
- For an 18×18 insert, use a 16×16 or 17×17 cover.
- For a 22×22 insert, use a 20×20 or 21×21 cover.
This rule applies to most standard pillow forms, like poly-fill or feather/down blends. It’s a good starting point for any project.
Exceptions to the Standard Rule
Not every pillow style aims for a super plump look. Sometimes, you want a softer, more relaxed appearance. In these cases, you can use a cover that is the same size as the insert, or even slightly larger.
- Linen or Slub Cotton Covers: These fabrics often have a casual, lived-in aesthetic. A 20×20 cover on a 20×20 insert gives a softer drape.
- Knit or Sweater Covers: These stretchy materials conform to the insert, so sizing down isn’t always necessary.
- Decorative Sham with Closure: If a sham has a wide overlap closure (like a 5-inch flange), you might use a same-size insert to avoid bulk under the flange.
Choosing Based on Insert Material
The type of filling in your 20×20 insert also affects your cover choice.
- Down or Feather Blends: These inserts are very compressible and fluff up a lot. You can safely use an 18×18 cover for a very full look, as the down will compress and then expand.
- Polyester Fiberfill (Poly-fill): These are firmer and less compressible. A 19×19 cover might be a safer bet to avoid over-stuffing, unless you want an extremely firm pillow.
- Foam Inserts: Solid foam inserts have no give. You must use a cover that is at least the same size, often 20×20 or even 21×21, to get it to fit at all.
Step-by-Step: How to Measure Your Insert for the Perfect Cover
If your insert is old, misshapen, or non-standard, don’t guess. Follow these steps to measure it correctly.
- Fluff Your Insert: Shake and punch your insert to restore it’s full shape. Let it sit for an hour after fluffing.
- Lay it Flat: Place the insert on a flat surface, like a table or the floor.
- Measure Width and Height: Using a soft measuring tape, measure the width from seam to seam. Then measure the height. Do this in a few spots, as inserts can settle unevenly.
- Note the Fullest Measurement: Take the largest measurement you get for each dimension. If your “20×20” insert actually measures 20.5 x 21, use those numbers.
- Apply the 2-Inch Rule: Subtract 1-2 inches from your measured dimensions to find your ideal cover size. For a 20.5 x 21 insert, a 19×19 or 18×20 cover could work.
Pillow Cover Closure Types and How They Affect Fit
The way your pillow cover closes also plays a role in the final look and fit.
- Zipper Closure: Offers the cleanest look and holds the insert securely. Best for a tight, plump fit with a smaller cover.
- Envelope Closure: A simple overlapping flap. It can sometimes gape open if the insert is too large and creates too much pressure. A 19×19 cover might be better than an 18×18 for this style.
- Knife-Edge or No Closure (Insertion Style): These covers are sewn shut around the insert. You must follow the size rule precisely, as you can’t remove the insert easily.
- Button or Tie Closure: Similar to envelope, but can be adjusted for a slightly looser or tighter fit depending on how you fasten it.
Common Mistakes to Avoid When Sizing Pillow Covers
Even with the rules, its easy to make a mistake. Here are the most common pitfalls.
- Using a 20×20 Cover for a 20×20 Insert: This is the number one error. It leads to a flat, underfilled pillow that loses its shape quickly.
- Ignoring Insert Loft: A new, high-loft insert needs more room to expand than a flat, old one. Consider the insert’s condition.
- Forgetting About Fabric Shrinkage: If you’re making a cover from a fabric like cotton, pre-wash it! It can shrink, turning your perfect 18×18 cover into a 17.5×17.5, making it too tight.
- Mixing Metric and Imperial: Double-check if the cover listing is in inches or centimeters. A 50×50 cm cover is not the same as a 20×20 inch cover (it’s closer to 19.7×19.7).
How to Fix a Pillow Cover That is the Wrong Size
Don’t worry if you already have a mismatched set. You can often fix it.
If the Cover is Too Big: The pillow will look deflated and messy. Solution: You can sometimes wash and dry the cover on high heat to shrink it slightly (check fabric care first). The best fix is to buy a larger insert. A 22×22 insert in a 20×20 cover will give you the correct fullness.
If the Cover is Too Small: The pillow will be overstuffed, seams will strain, and the closure may pop open. Solution: The safest fix is to buy a smaller insert, like an 18×18. If you’re handy, you can carefully open a seam on your insert and remove some filling until it fits comfortably.
Special Styles: Euro Shams, Bolsters, and Lumbar Pillows
The 2-inch rule applies to most square pillows, but other shapes have there own guidelines.
- Euro Sham (26×26): These are meant to be back pillows and have a specific, flatter look. Often, a 26×26 Euro sham uses a 26×26 insert or a 24×24 insert for a less bulky feel behind your head.
- Lumbar Pillows (12×24, 14×28): For a plump lumbar, the cover should be 1-2 inches smaller in both dimensions. A 12×24 lumbar insert works best in a 10×22 or 11×23 cover.
- Bolster Pillows: Measure the diameter and length. The cover’s diameter should be the same or slightly smaller than the bolster’s diameter for a snug fit.
Where to Buy Correctly Sized Pillow Covers and Inserts
Always check product descriptions carefully when shopping online. Reputable home goods stores will list the finished cover size and often recommend an insert size.
- Look for phrases like “Fits a 20×20 insert” or “Finished size: 18×18”.
- Read customer reviews. People often mention if the item runs large or small.
- Consider buying a cover and insert as a set from the same retailer to guarantee compatibility.
- For custom sizes, many Etsy sellers and fabric stores will make covers to your exact specifications.
DIY Pillow Covers: Cutting Fabric to the Right Size
Making your own cover? Here’s the simple math for a simple envelope closure cover for a 20×20 insert.
- Decide on Your Finished Size: Let’s say you want an 18×18 finished cover.
- Add Seam Allowance: Add 1/2 inch to each side for seams. So, each front panel should be cut to 19×19 inches (18 + 0.5 + 0.5).
- Cut the Back Panels: For the envelope back, you need two overlapping pieces. Cut two rectangles. Their width should be your finished width plus seam allowance (19 inches). Their height should be (finished height / 2) + 4 inches for the overlap. So, (18/2) + 4 = 13 inches. Cut two back pieces at 19×13 inches.
This will give you a perfect, custom-fit cover for your insert.
Final Checklist Before You Buy or Sew
Quickly run through this list to ensure you get the perfect fit.
- ✓ I have measured my existing insert or know the exact size I need to buy.
- ✓ I want a [ ] Plump / [ ] Standard / [ ] Soft look.
- ✓ I have chosen a cover size that is 1-2 inches smaller than my insert for a plump look.
- ✓ I have considered my insert material (down = more compressible, foam = not compressible).
- ✓ I have noted the closure type and how it might affect fit.
- ✓ I have checked for potential fabric shrinkage if making or buying a natural fiber cover.
FAQ: Your Pillow Sizing Questions Answered
Can I use a 20×20 insert in a 20×20 cover?
You can, but you probably shouldn’t. It will result in a flat, underfilled pillow that lacks shape. For a polished look, the cover should be smaller.
What is the best size cover for a 20 inch pillow form?
The best size is an 18×18 inch cover. This creates the ideal amount of fullness and a professional finish.
Is 18×18 or 19×19 better for a 20×20 insert?
An 18×18 cover will give a fuller, plumper look. A 19×19 cover offers a slightly softer, but still neat, appearance. Choose based on your desired firmness and the insert’s material.
How do I make my pillows look fluffier?
Use a smaller cover, choose a down or feather blend insert, and fluff them regularly. The tension from the smaller cover is the main trick.
Why does my pillow cover look wrinkly?
This is often because the cover is too big for the insert. The fabric isn’t stretched taut, so it wrinkles. Switching to a smaller cover or larger insert will smooth it out.
Can I put two inserts in one cover?
Sometimes, for a very firm look, people use two thinner inserts in one cover. This is tricky, though. You’d need a cover significantly larger than a single insert to fit two, and it can look lumpy. It’s usually not recommended.
Getting the right size pillow cover for your 20×20 insert is a small detail with a huge impact. By following the simple rule of choosing a cover that is 1 to 2 inches smaller, you ensure your pillows always look crisp, inviting, and professionally styled. Remember to consider your insert type and desired look, and you’ll never have a limp or overstuffed pillow again.